Ultrasound transducer dual frequency

A transducer (10) ultrasonic dual frequency, comprising a substrate (14); and a single element (12) attached to the substrate piezoelectric wherein the diameter of the substrate is greater than the diameter of the piezoelectric element; means able to excite the transducer on a mechanical resonant mode bending low frequency by applying a voltage to the piezoelectric element, which includes an oscillating component in the low frequency range 20 kHz to 500 kHz; and means able to excite the transducer on a resonance mode thick high frequency by applying a voltage to the piezoelectric element, comprising an oscillatory high frequency component in the range of 500 kHz to 5 MHz.